Controllers can be set up to change flashing or animation styles by pressing a button or turning a dial on the unit; others have only one pattern, but the speed of this pattern can usually be adjusted by turning a similar dial.

Christmas tree lights are a big part of the holiday season. As November and December roll around, you might see strands of lights everywhere -- on artificial Christmas trees, houses, shrubs, bushes and even the occasional car! Have you ever wondered how these lights work? Why is it that if you pull out or break one of the bulbs, the whole strand of lights goes out? And how do they create the lights that sequence in different color patterns?